The present invention generally relates to fire-resistant coated building panels.
German Patent DE 196 14 296 C2 describes a wall element with a fiber mat and a coating including particles in the form of quartz sand and a binder. In the coating material there are two different particle contributions. A main part of the particles shows a narrow variation in size and a second part has a small size below 0,1 mm. The particles are bonded by organic resin, wherein preferably two different resin dispersions can be used, an acrylic resin or a polymeric dispersion. The binder together with the small sized particles is building slightly elastic bridges between the bigger sized particles. The disadvantage of this coating is the fact, that the resin is not fire-resistant.
A coating composition containing a binder composed mainly of silica gel has been proposed for example in U.S. Pat. No. 4,059,553. For gel formation quarternary ammonium with alkyl groups and hydroxyalkyl groups, each containing from 1 to 20 carbon atoms, are added. In the examples quarternary ammonium is occurring in the form of monomethyltripropanolammonium, dimethyldipropanolammonium, monomethyltriethanolammonium or tetraethanolammonium. Due to the organic alkyl groups this binder has not the required fire-resistance. There are different silica based binders described for example in the patents U.S. Pat. No. 2,244,325, U.S. Pat. No. 2,726,216, and U.S. Pat. No. 5,964,693 but there is no coating mass described with these binders.
U.S. Pat. No. 4,002,590 describes a coating composition with a colloidal silica and an organic polymer in a low content by weight. The binder, consisting of a colloidal silica and an organic polymer, is rather fire resistant because of the low content of organic polymer. A main constituent of the coating composition is a powder of silica and calcium carbonate. The resulting coating has a high density. According to U.S. Pat. No. 4,002,590 it can be applied to concrete surfaces, slate board, calcium silicate board, gypsum board, plywood board or metal plate. It turned out that the heat is transferred very easily by this coating. In the case of fire the heat reaches very fast the board on which the coating is fixed. Therefore the coating does not prevent the board or underlying building material from burning within a short time.
In view of the foregoing, an object of at least one embodiment of the invention is to provide coated building panels with high fire-resistance and low heat transfer coefficients.
Another object of at least one embodiment of the invention is to provide coated building panels which can be easily produced and mounted.
Another object of at least one embodiment of the invention is to provide coated building panels which can be used for esthetically decorating the ceiling and or walls of rooms.